1. Field of the Invention
The present invention relates to a polyarylene sulfide resin composition which has been improved in impact resistance and besides with which molded products having excellent appearance can be produced.
2. Related Art
Compositions in which the impact resistance of a polyarylene sulfide resin has been improved are proposed in Japanese Patent Application Kokai Nos. 56-118456, 58-154757, 59-207921, 61-21156, W089/00181, etc. These compositions are those obtained by blending the polyarylene sulfide resin with various rubber components such as a styrene/butadiene block copolymer, ethylene/glycidyl methacrylate copolymer, ethylene/butene copolymer, EP rubber and the like.
However, such compositions have problems that: The molding temperature of the polyarylene sulfide resin is as high as 290.degree. C. or more, and in such a temperature region, the common diene rubber components and olefin rubber components deteriorate by heat, so that it is difficult to say that a sufficient effect can be obtained in improving the impact resistance. And also, molded products obtained from such compositions are inferior in appearance.
As compositions intended to improve the above defects, a blend of the polyarylene sulfide resin and a polyorganosiloxane rubber is proposed in EP-A2-0142825. Since, however, this polyorganosiloxane rubber is crumbs of a crosslinked silicone rubber and also the silicone rubber is poor in compatibility with the polyarylene sulfide resin, there is a problem that sufficient improvement in the impact strength cannot be attained.
For this reason, the present applicants previously proposed a composition obtained by adding a polyorganosiloxane graft copolymer to the polyarylene sulfide resin in EP-A2-0332188 and EP-A2-0369245, and a composition obtained by blending the polyarylene sulfide resin, a polyorganosiloxane rubber and a particular organic silane compound in EP-A2-0369244.
The composition obtained by adding a polyorganosiloxane graft copolymer to the polyarylene sulfide resin has a markedly improved impact resistance as compared with the common compositions obtained by blending the polyarylene sulfide resin and a diene rubber or a polyolefin rubber. However, there are uses in which a further higher impact strength than that of the above composition is required. The composition obtained by blending the polyarylene sulfide resin, a polyorganosiloxane rubber and a particular organic silane compound is in a satisfactory level in terms of development of impact strength but it has a problem that molded products obtained therefrom has a poor appearance.